Weight training has traditionally been done using free weights. Free weights comprise a plurality of individual weights that can be loaded in various configurations onto the ends of a weight lifting bar. Each free weight has a central bore to allow the weight to be slipped onto the end of the bar. Free weights are usually circular in shape and are made in large quantities out of cast iron or the like.
Free weights are quite efficient in accommodating relatively large numbers of users. This is so because different users will usually not require the same amount of weight when exercising. While one user might need 200 pounds for a workout, the next user might only require 50 pounds, a third user 25 pounds, and so on. Thus, the individual users simply use the numbers of free weights that they require. The other free weights are available for use by other users.
However, free weights have some disadvantages. For one thing, to adjust the exercise mass, the user must add or subtract weight from the weight lifting bar. This can be time consuming and annoying when the user needs a different exercise mass for each different exercise. In such a case, after finishing one exercise, the user must stop and adjust the number of free weights carried by the bar before beginning the next exercise.
In addition, free weights or a weight lifting bar carrying such weights can be accidentally dropped by the user. This is particularly true if the user has loaded too much weight on the bar or is a relatively inexperienced weight lifter. This poses a safety risk. The user or a bystander can be injured if a bar or a free weight is dropped and strikes the user or the bystander.
As a consequence, various exercise machines have been developed that use a weight stack for providing the exercise mass. The weight stack typically comprises a vertical array of weights permanently carried on the machine in a location that poses no risk to the user. The top of the weight stack is coupled by a cable to some type of exercise implement carried on the machine, such as a lat pull down bar.
In such an exercise machine, the user adjusts the exercise mass by moving a selector pin to different vertical locations in the weight stack. This couples the weight which has been pinned and all the weights above the pinned weight to the exercise implement. Thus, when the user moves the exercise implement while performing an exercise, all of the selected weights in the weight stack are elevated to form the exercise mass. The remaining unselected weights in the lower unused portion of the weight stack simply remain stationary on the machine.
Exercise machines of this type can be single purpose machines for performing a single exercise or can be multiple purpose machines for performing multiple exercises. However, regardless of which machine is at issue, the weight stack must be quite large to allow the user to select a high exercise mass if that is what the user desires. Thus, if a user wishes to lift 200 pounds, each machine must have at least 200 pounds of weight in the weight stack even though many other users of the machine might never lift that much weight. Consequently, such exercise machines are relatively “wasteful” since they must necessarily provide a large amount of available weight even though much of this weight is never used at any given time by most users of the machine.
In addition, it is difficult to accommodate a large number of users using exercise machines alone. The number of machines determines the maximum number of users. In a system using just single purpose machines, if two users want to simultaneously use the same machine for doing the same exercise, one user must wait even though all the rest of the exercise machines might be idle. This problem can be avoided in a system in which each exercise machine is a multiple purpose machine, but each multiple purpose machine is somewhat more complex and expensive than a single purpose machine. In addition, if there are only 5 or 10 such machines in the system, then only 5 or 10 users can exercise simultaneously at one time.
Certain exercise machines have been developed that utilize a weight carried on a pivotal lever as the exercise mass. In such machines, the position of the weight can be adjusted along the lever to vary or adjust the exercise resistance provided by the exercise mass. Thus, this machine allows a greater variation in exercise resistance even though the exercise mass used on the lever might be relatively small. For example, a 25 pound weight can give more than 25 pounds of exercise resistance depending upon how far it is moved away from the pivot axis of the lever. The Paramount Direct Power machine is an example of this type of exercise machine.
However, with known pivotal lever machines, only a single user can use the machine at a given time. The slidable weight carried on the pivotal lever cannot be removed completely or in increments for use by other users. The slidable weight must remain on the exercise machine at all times.
The assignee of this invention previously made and sold an exercise machine known as the PowerBlock Gym. This machine had an exercise station at which the user could perform multiple exercises using different exercise implements. However, rather than using a conventional weight stack, the exercise mass was formed by a pair of the assignee's adjustable selectorized dumbbells known as PowerBlock dumbbells. These dumbbells were carried on a vertically sliding tray that moved up and down a rear upright of the machine.
One advantage of the PowerBlock Gym was that the selectorized dumbbells forming the exercise mass could be wholly or partially removed and used by other users even while a first user was using the Gym. For example, if one dumbbell were removed from the tray and used as a dumbbell, the second dumbbell could remain on the tray and be used as the exercise mass of the machine. Alternatively, both of the dumbbells could be partially loaded with weight and removed for use as dumbbells. The remaining unselected weights of each dumbbell, namely the weights that were not coupled to the handles of the dumbbells, would remain on the tray for use by a user of the PowerBlock Gym.
While the PowerBlock Gym theoretically expanded the numbers of users that could exercise at one time, it was not a truly effective solution to the problem of getting optimum use from the machine. For example, each PowerBlock dumbbell weighed a maximum of 85 pounds. Thus, when two fully loaded dumbbells were contained on the tray, the maximum exercise mass was 170 pounds. This is not sufficient for some users when doing some exercises. There was no way to easily and effectively increase the exercise mass.
In addition, when one dumbbell was removed or both dumbbells were partially removed for use as dumbbells, the PowerBlock Gym could still be used by another user as noted above. However, in this situation, the exercise mass was reduced by the amount of the removed mass of the dumbbells. For example, if one complete dumbbell were removed, then the maximum exercise mass decreased by 85 pounds from 170 pounds to 85 pounds. As a practical matter, the PowerBlock Gym became almost unusable if too much of the weight of the selectorized dumbbells was removed from the tray.
Finally, in the PowerBlock Gym, it could be difficult or awkward to remove the selectorized dumbbells from the tray. The tray was inclined towards the rear of the exercise machine and was located behind a rear upright. A user could dismount the machine and walk around in back of the machine to lift one of the PowerBlock dumbbells up out of the tray. However, many users found the need to dismount the machine an annoyance.
Consequently, many users tried to remove the PowerBlock dumbbells from the tray by reaching to the rear from the front of the machine. However, in its normal lowermost position, the tray carrying the dumbbells was located at least partially behind the back rest of the exercise bench. Thus, the user would have to reach over or around the back rest to get to the selectorized dumbbells.
Moreover, the upright which carried the tray was located directly in the way of the user's head. Thus, some users might hit their heads on the upright when attempting to reach the dumbbells from the front of the machine. In addition, the tray carrying the dumbbells was inclined towards the rear of the machine or away from a user attempting to reach the tray from the front of the machine. Thus, it was difficult to remove the PowerBlock dumbbells from the front of the PowerBlock Gym.
Accordingly, there is a need in the art for an exercise machine that provides an exercise mass that is adjustable to provide a wide range of exercise resistance, but that also allows multiple users to simultaneously exercise using at least some portions of the exercise mass that can be easily removed from the machine.